A roll paper supply mechanism reliably prevents roll paper from rising from a desired position. The roll paper supply mechanism 3 of a roll paper printer 1 has an urging member 41 that urges the round end surface of the roll paper 2 to the roll paper guide 33 defining one side of the roll paper storage unit 31. The urging surface 41a of the urging member 41 is inclined to the inside in the pulling direction A of the recording paper 2a that is pulled from the roll paper 2. When seen from the side of the width of the roll paper storage unit 31, the urging surface 41a is disposed between a vertical line V through the center of gravity G of the roll paper and the recording paper pulling position D, and urges an outside edge part 2d of the roll paper 2 at a position above the recording paper pulling position D. Because the urging surface 41a prevents the roll paper 2 from rising in the direction in which the recording paper 2a is pulled from the roll paper 2, and produces a moment centered on the urging position that prevents the roll paper 2 from rising, the roll paper 2 can be reliably prevented from rising and from bouncing up and down.